Democrats panicked by third-party candidates drawing support away from Hillary Clinton are ramping up their attacks against Gary Johnson and warning that a vote for a third party is a vote for Donald Trump.

Liberal groups are passing around embarrassing videos of Johnson and running ads against him warning about his positions on issues like climate change that are important to young voters and independents.

The Clinton campaign will rely heavily on Sen. Bernie Sanders (I-Vt.) in the coming weeks as it seeks to shore up its deficit among young voters and left-leaning independents who are not energized by her campaign and are considering casting a vote for either Johnson or Green Party nominee Jill Stein.

The Libertarian ticket of Johnson and Bill Weld is running surprisingly strong among young voters — a cog in the Obama coalition that Democrats need to turn out for Clinton if she’s to pull away from Trump.

Whether Clinton reaches those voters could determine the outcome of critical battleground states like Colorado, Nevada and Pennsylvania.

If Democrats are worried about defeating the Libertarian candidate, their internal polling must be much worse than they’re telling anyone.

Plus, any time and money they put into attacking Johnson could have used to attack Trump.